Thank you for your answer. But I have interest in finding some computational methods to extract a sort of greyscale map locating the pre-attentive elements of a scene. These elements are fundamental aspects of the entire visual stream from a perceptual viewpoint. Thank you again for your attention

As far as I know, most c-models are about goal driven or (covert) attention eye movement. But you can have a look at this: Gao & Vasconcelos 2004, Adv. in neural info process. systems, 17(481-488). As to bottom up models have a look also at Harel et al. 2007, Adv. in neural info. process. systems, 19, 545; Peters et al. 2005, Vis. Res. 45(8), 2397{2416. Although not on computation it's inetresting: Martinez-Conde, Macknik 2015 Perception, 884-889